Initial attempt at implementing Display Traits

Initial attempt to get display traits working with ASEnvironment.

To get proper ASDisplayTraits support, you must use an ASViewController. The ASViewController implements UITraitCollection-related methods (`traitCollectionDidChange:`, `willTransitionToTraitCollection:withTransitionCoordinator:`, viewWillTransitionToSize:withTransitionCoordinator`) to update the internal ASDisplayTraits and propagate them to subnodes.

ASTableNode and ASCollectionNode don't actually have their cells as subnodes, so a little bit of trickery is involved (on `setEnvironment:` the table/collection node gets its data controllers completedNodes and propagates the new traits. see `ASDisplayTraitsCollectionTableSetEnvironmentState`). The data controller also passes the current display traits when creating new cells.

ASViewController also supports the ability to return a custom set of display traits. So if you have a modal dialog that should always be told it is in a compact size class, you can set the override block before displaying the VC.

A new example, called Display Traits, has been added. It shows how display traits can be used in a ASViewController with a normal ASDisplayNode as its root, as well as in ASViewControllers hosting table nodes and collection nodes. There is also an example of overriding the default display traits of a VC.

Please provide feedback!

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -190,7 +190,6 @@
 		25E327581C16819500A2170C /* ASPagerNode.m in Sources */ = {isa = PBXBuildFile; fileRef = 25E327551C16819500A2170C /* ASPagerNode.m */; };
 		25E327591C16819500A2170C /* ASPagerNode.m in Sources */ = {isa = PBXBuildFile; fileRef = 25E327551C16819500A2170C /* ASPagerNode.m */; };
 		2767E9411BB19BD600EA9B77 /* ASViewController.h in Headers */ = {isa = PBXBuildFile; fileRef = ACC945A81BA9E7A0005E1FB8 /* ASViewController.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		2767E9421BB19BD600EA9B77 /* ASViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = ACC945AA1BA9E7C1005E1FB8 /* ASViewController.m */; };
 		2911485C1A77147A005D0878 /* ASControlNodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 2911485B1A77147A005D0878 /* ASControlNodeTests.m */; };
 		291B63FB1AA53A7A000A71B3 /* ASScrollDirection.h in Headers */ = {isa = PBXBuildFile; fileRef = 296A0A311A951715005ACEAA /* ASScrollDirection.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		292C599F1A956527007E5DD6 /* ASLayoutRangeType.h in Headers */ = {isa = PBXBuildFile; fileRef = 292C59991A956527007E5DD6 /* ASLayoutRangeType.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -275,8 +274,6 @@
 		68EE0DC01C1B4ED300BA1B99 /* ASMainSerialQueue.mm in Sources */ = {isa = PBXBuildFile; fileRef = 68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */; };
 		698548631CA9E025008A345F /* ASEnvironment.h in Headers */ = {isa = PBXBuildFile; fileRef = 698548611CA9E025008A345F /* ASEnvironment.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		698548641CA9E025008A345F /* ASEnvironment.h in Headers */ = {isa = PBXBuildFile; fileRef = 698548611CA9E025008A345F /* ASEnvironment.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		698548651CA9E025008A345F /* ASEnvironment.m in Sources */ = {isa = PBXBuildFile; fileRef = 698548621CA9E025008A345F /* ASEnvironment.m */; };
-		698548661CA9E025008A345F /* ASEnvironment.m in Sources */ = {isa = PBXBuildFile; fileRef = 698548621CA9E025008A345F /* ASEnvironment.m */; };
 		698C8B611CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */ = {isa = PBXBuildFile; fileRef = 698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		698C8B621CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */ = {isa = PBXBuildFile; fileRef = 698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		69CB62AB1CB8165900024920 /* _ASDisplayViewAccessiblity.h in Headers */ = {isa = PBXBuildFile; fileRef = 69CB62A91CB8165900024920 /* _ASDisplayViewAccessiblity.h */; };
@@ -336,6 +333,9 @@
 		9C8898BD1C738BB800D6B02E /* ASTextKitFontSizeAdjuster.h in Headers */ = {isa = PBXBuildFile; fileRef = A32FEDD31C501B6A004F642A /* ASTextKitFontSizeAdjuster.h */; };
 		9CDC18CC1B910E12004965E2 /* ASLayoutablePrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 9CDC18CB1B910E12004965E2 /* ASLayoutablePrivate.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		9CDC18CD1B910E12004965E2 /* ASLayoutablePrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 9CDC18CB1B910E12004965E2 /* ASLayoutablePrivate.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		9CFFC6BE1CCAC52B006A6476 /* ASEnvironment.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9CFFC6BD1CCAC52B006A6476 /* ASEnvironment.mm */; };
+		9CFFC6C01CCAC73C006A6476 /* ASViewController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9CFFC6BF1CCAC73C006A6476 /* ASViewController.mm */; };
+		9CFFC6C21CCAC768006A6476 /* ASTableNode.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9CFFC6C11CCAC768006A6476 /* ASTableNode.mm */; };
 		9F06E5CD1B4CAF4200F015D8 /* ASCollectionViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.m */; };
 		A2763D791CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h in Headers */ = {isa = PBXBuildFile; fileRef = A2763D771CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h */; };
 		A2763D7A1CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h in Headers */ = {isa = PBXBuildFile; fileRef = A2763D771CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h */; };
@@ -362,7 +362,6 @@
 		AC7A2C171BDE11DF0093FE1A /* ASTableViewInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */; };
 		AC7A2C181BDE11DF0093FE1A /* ASTableViewInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */; };
 		ACC945A91BA9E7A0005E1FB8 /* ASViewController.h in Headers */ = {isa = PBXBuildFile; fileRef = ACC945A81BA9E7A0005E1FB8 /* ASViewController.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		ACC945AB1BA9E7C1005E1FB8 /* ASViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = ACC945AA1BA9E7C1005E1FB8 /* ASViewController.m */; };
 		ACF6ED1A1B17843500DA7C62 /* ASBackgroundLayoutSpec.h in Headers */ = {isa = PBXBuildFile; fileRef = ACF6ED011B17843500DA7C62 /* ASBackgroundLayoutSpec.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		ACF6ED1B1B17843500DA7C62 /* ASBackgroundLayoutSpec.mm in Sources */ = {isa = PBXBuildFile; fileRef = ACF6ED021B17843500DA7C62 /* ASBackgroundLayoutSpec.mm */; };
 		ACF6ED1C1B17843500DA7C62 /* ASCenterLayoutSpec.h in Headers */ = {isa = PBXBuildFile; fileRef = ACF6ED031B17843500DA7C62 /* ASCenterLayoutSpec.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -405,7 +404,6 @@
 		AEEC47E21C20C2DD00EC1693 /* ASVideoNode.mm in Sources */ = {isa = PBXBuildFile; fileRef = AEEC47E01C20C2DD00EC1693 /* ASVideoNode.mm */; };
 		AEEC47E41C21D3D200EC1693 /* ASVideoNodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = AEEC47E31C21D3D200EC1693 /* ASVideoNodeTests.m */; };
 		B0F8805A1BEAEC7500D17647 /* ASTableNode.h in Headers */ = {isa = PBXBuildFile; fileRef = B0F880581BEAEC7500D17647 /* ASTableNode.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		B0F8805B1BEAEC7500D17647 /* ASTableNode.m in Sources */ = {isa = PBXBuildFile; fileRef = B0F880591BEAEC7500D17647 /* ASTableNode.m */; };
 		B13CA0F71C519E9400E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h in Headers */ = {isa = PBXBuildFile; fileRef = B13CA0F61C519E9400E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		B13CA0F81C519EBA00E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h in Headers */ = {isa = PBXBuildFile; fileRef = B13CA0F61C519E9400E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		B13CA1001C52004900E031AB /* ASCollectionNode+Beta.h in Headers */ = {isa = PBXBuildFile; fileRef = B13CA0FF1C52004900E031AB /* ASCollectionNode+Beta.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -499,7 +497,6 @@
 		B350625D1B0111740018CF92 /* Photos.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 051943141A1575670030A7D0 /* Photos.framework */; };
 		B350625E1B0111780018CF92 /* AssetsLibrary.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 051943121A1575630030A7D0 /* AssetsLibrary.framework */; };
 		B350625F1B0111800018CF92 /* Foundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 058D09AF195D04C000B7D73C /* Foundation.framework */; };
-		C78F7E2A1BF7808300CDEAFC /* ASTableNode.m in Sources */ = {isa = PBXBuildFile; fileRef = B0F880591BEAEC7500D17647 /* ASTableNode.m */; };
 		C78F7E2B1BF7809800CDEAFC /* ASTableNode.h in Headers */ = {isa = PBXBuildFile; fileRef = B0F880581BEAEC7500D17647 /* ASTableNode.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		CC3B20831C3F76D600798563 /* ASPendingStateController.h in Headers */ = {isa = PBXBuildFile; fileRef = CC3B20811C3F76D600798563 /* ASPendingStateController.h */; };
 		CC3B20841C3F76D600798563 /* ASPendingStateController.h in Headers */ = {isa = PBXBuildFile; fileRef = CC3B20811C3F76D600798563 /* ASPendingStateController.h */; };
@@ -779,7 +776,6 @@
 		68EE0DBB1C1B4ED300BA1B99 /* ASMainSerialQueue.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASMainSerialQueue.h; sourceTree = "<group>"; };
 		68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASMainSerialQueue.mm; sourceTree = "<group>"; };
 		698548611CA9E025008A345F /* ASEnvironment.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASEnvironment.h; sourceTree = "<group>"; };
-		698548621CA9E025008A345F /* ASEnvironment.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASEnvironment.m; sourceTree = "<group>"; };
 		698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASLayoutableExtensibility.h; path = AsyncDisplayKit/Layout/ASLayoutableExtensibility.h; sourceTree = "<group>"; };
 		69CB62A91CB8165900024920 /* _ASDisplayViewAccessiblity.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = _ASDisplayViewAccessiblity.h; sourceTree = "<group>"; };
 		69CB62AA1CB8165900024920 /* _ASDisplayViewAccessiblity.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = _ASDisplayViewAccessiblity.mm; sourceTree = "<group>"; };
@@ -809,6 +805,9 @@
 		9C8221941BA237B80037F19A /* ASStackBaselinePositionedLayout.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASStackBaselinePositionedLayout.mm; sourceTree = "<group>"; };
 		9C8898BA1C738B9800D6B02E /* ASTextKitFontSizeAdjuster.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = ASTextKitFontSizeAdjuster.mm; path = TextKit/ASTextKitFontSizeAdjuster.mm; sourceTree = "<group>"; };
 		9CDC18CB1B910E12004965E2 /* ASLayoutablePrivate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASLayoutablePrivate.h; path = AsyncDisplayKit/Layout/ASLayoutablePrivate.h; sourceTree = "<group>"; };
+		9CFFC6BD1CCAC52B006A6476 /* ASEnvironment.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASEnvironment.mm; sourceTree = "<group>"; };
+		9CFFC6BF1CCAC73C006A6476 /* ASViewController.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASViewController.mm; sourceTree = "<group>"; };
+		9CFFC6C11CCAC768006A6476 /* ASTableNode.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASTableNode.mm; sourceTree = "<group>"; };
 		9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; lineEnding = 0; path = ASCollectionViewTests.m; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objc; };
 		A2763D771CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASPINRemoteImageDownloader.h; path = Details/ASPINRemoteImageDownloader.h; sourceTree = "<group>"; };
 		A2763D781CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = ASPINRemoteImageDownloader.m; path = Details/ASPINRemoteImageDownloader.m; sourceTree = "<group>"; };
@@ -828,7 +827,6 @@
 		AC6456071B0A335000CF11B8 /* ASCellNode.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASCellNode.mm; sourceTree = "<group>"; };
 		AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASTableViewInternal.h; sourceTree = "<group>"; };
 		ACC945A81BA9E7A0005E1FB8 /* ASViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASViewController.h; sourceTree = "<group>"; };
-		ACC945AA1BA9E7C1005E1FB8 /* ASViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASViewController.m; sourceTree = "<group>"; };
 		ACF6ED011B17843500DA7C62 /* ASBackgroundLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASBackgroundLayoutSpec.h; path = AsyncDisplayKit/Layout/ASBackgroundLayoutSpec.h; sourceTree = "<group>"; };
 		ACF6ED021B17843500DA7C62 /* ASBackgroundLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; name = ASBackgroundLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASBackgroundLayoutSpec.mm; sourceTree = "<group>"; };
 		ACF6ED031B17843500DA7C62 /* ASCenterLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASCenterLayoutSpec.h; path = AsyncDisplayKit/Layout/ASCenterLayoutSpec.h; sourceTree = "<group>"; };
@@ -872,7 +870,6 @@
 		AEEC47E01C20C2DD00EC1693 /* ASVideoNode.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASVideoNode.mm; sourceTree = "<group>"; };
 		AEEC47E31C21D3D200EC1693 /* ASVideoNodeTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASVideoNodeTests.m; sourceTree = "<group>"; };
 		B0F880581BEAEC7500D17647 /* ASTableNode.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASTableNode.h; sourceTree = "<group>"; };
-		B0F880591BEAEC7500D17647 /* ASTableNode.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASTableNode.m; sourceTree = "<group>"; };
 		B13CA0F61C519E9400E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASCollectionViewLayoutFacilitatorProtocol.h; sourceTree = "<group>"; };
 		B13CA0FF1C52004900E031AB /* ASCollectionNode+Beta.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "ASCollectionNode+Beta.h"; sourceTree = "<group>"; };
 		B30BF6501C5964B0004FCD53 /* ASLayoutManager.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASLayoutManager.h; path = TextKit/ASLayoutManager.h; sourceTree = "<group>"; };
@@ -1073,7 +1070,7 @@
 				D785F6601A74327E00291744 /* ASScrollNode.h */,
 				D785F6611A74327E00291744 /* ASScrollNode.m */,
 				B0F880581BEAEC7500D17647 /* ASTableNode.h */,
-				B0F880591BEAEC7500D17647 /* ASTableNode.m */,
+				9CFFC6C11CCAC768006A6476 /* ASTableNode.mm */,
 				055F1A3219ABD3E3004DAFF1 /* ASTableView.h */,
 				055F1A3319ABD3E3004DAFF1 /* ASTableView.mm */,
 				AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */,
@@ -1082,7 +1079,7 @@
 				A373200E1C571B050011FC94 /* ASTextNode+Beta.h */,
 				058D09E0195D050800B7D73C /* ASTextNode.mm */,
 				ACC945A81BA9E7A0005E1FB8 /* ASViewController.h */,
-				ACC945AA1BA9E7C1005E1FB8 /* ASViewController.m */,
+				9CFFC6BF1CCAC73C006A6476 /* ASViewController.mm */,
 				6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */,
 				764D83D21C8EA515009B4FB8 /* AsyncDisplayKit+Debug.h */,
 				764D83D31C8EA515009B4FB8 /* AsyncDisplayKit+Debug.m */,
@@ -1167,6 +1164,7 @@
 		058D09E1195D050800B7D73C /* Details */ = {
 			isa = PBXGroup;
 			children = (
+				9CFFC6BD1CCAC52B006A6476 /* ASEnvironment.mm */,
 				058D09E2195D050800B7D73C /* _ASDisplayLayer.h */,
 				058D09E3195D050800B7D73C /* _ASDisplayLayer.mm */,
 				058D09E4195D050800B7D73C /* _ASDisplayView.h */,
@@ -1187,7 +1185,6 @@
 				05A6D05819D0EB64002DD95E /* ASDealloc2MainObject.h */,
 				05A6D05919D0EB64002DD95E /* ASDealloc2MainObject.m */,
 				698548611CA9E025008A345F /* ASEnvironment.h */,
-				698548621CA9E025008A345F /* ASEnvironment.m */,
 				4640521B1A3F83C40061C0BA /* ASFlowLayoutController.h */,
 				4640521C1A3F83C40061C0BA /* ASFlowLayoutController.mm */,
 				058D09E6195D050800B7D73C /* ASHighlightOverlayLayer.h */,
@@ -1982,6 +1979,7 @@
 				92DD2FE41BF4B97E0074C9DD /* ASMapNode.mm in Sources */,
 				DBC452DC1C5BF64600B16017 /* NSArray+Diffing.m in Sources */,
 				AC3C4A521A1139C100143C57 /* ASCollectionView.mm in Sources */,
+				9CFFC6C21CCAC768006A6476 /* ASTableNode.mm in Sources */,
 				205F0E1E1B373A2C007741D0 /* ASCollectionViewLayoutController.mm in Sources */,
 				058D0A13195D050800B7D73C /* ASControlNode.mm in Sources */,
 				464052211A3F83C40061C0BA /* ASDataController.mm in Sources */,
@@ -2007,7 +2005,6 @@
 				430E7C911B4C23F100697A4C /* ASIndexPath.m in Sources */,
 				ACF6ED231B17843500DA7C62 /* ASInsetLayoutSpec.mm in Sources */,
 				ACF6ED4C1B17847A00DA7C62 /* ASInternalHelpers.mm in Sources */,
-				698548651CA9E025008A345F /* ASEnvironment.m in Sources */,
 				ACF6ED251B17843500DA7C62 /* ASLayout.mm in Sources */,
 				DB55C2631C6408D6004EDCF5 /* _ASTransitionContext.m in Sources */,
 				92074A631CC8BA1900918F75 /* ASImageNode+tvOS.m in Sources */,
@@ -2050,13 +2047,13 @@
 				ACF6ED321B17843500DA7C62 /* ASStaticLayoutSpec.mm in Sources */,
 				AC026B6B1BD57D6F00BBC17E /* ASChangeSetDataController.m in Sources */,
 				68355B311CB5799E001D4E68 /* ASImageNode+AnimatedImage.mm in Sources */,
+				9CFFC6C01CCAC73C006A6476 /* ASViewController.mm in Sources */,
 				055F1A3519ABD3E3004DAFF1 /* ASTableView.mm in Sources */,
 				058D0A17195D050800B7D73C /* ASTextNode.mm in Sources */,
 				257754AC1BEE44CD00737CA5 /* ASTextKitRenderer.mm in Sources */,
-				ACC945AB1BA9E7C1005E1FB8 /* ASViewController.m in Sources */,
-				B0F8805B1BEAEC7500D17647 /* ASTableNode.m in Sources */,
 				205F0E221B376416007741D0 /* CGRect+ASConvenience.m in Sources */,
 				257754B21BEE44CD00737CA5 /* ASTextKitShadower.mm in Sources */,
+				9CFFC6BE1CCAC52B006A6476 /* ASEnvironment.mm in Sources */,
 				058D0A21195D050800B7D73C /* NSMutableAttributedString+TextKitAdditions.m in Sources */,
 				205F0E101B371875007741D0 /* UICollectionViewLayout+ASConvenience.m in Sources */,
 				CC7FD9DF1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.m in Sources */,
@@ -2121,8 +2118,6 @@
 				B35062421B010EFD0018CF92 /* _ASAsyncTransactionGroup.m in Sources */,
 				B350624A1B010EFD0018CF92 /* _ASCoreAnimationExtras.mm in Sources */,
 				68EE0DC01C1B4ED300BA1B99 /* ASMainSerialQueue.mm in Sources */,
-				698548661CA9E025008A345F /* ASEnvironment.m in Sources */,
-				2767E9421BB19BD600EA9B77 /* ASViewController.m in Sources */,
 				B35062101B010EFD0018CF92 /* _ASDisplayLayer.mm in Sources */,
 				9C55866B1BD54A1900B50E3A /* ASAsciiArtBoxCreator.m in Sources */,
 				B35062121B010EFD0018CF92 /* _ASDisplayView.mm in Sources */,
@@ -2207,7 +2202,6 @@
 				B350620B1B010EFD0018CF92 /* ASTableView.mm in Sources */,
 				B350620E1B010EFD0018CF92 /* ASTextNode.mm in Sources */,
 				68355B3E1CB57A60001D4E68 /* ASPINRemoteImageDownloader.m in Sources */,
-				C78F7E2A1BF7808300CDEAFC /* ASTableNode.m in Sources */,
 				509E68661B3AEDD7009B9150 /* CGRect+ASConvenience.m in Sources */,
 				254C6B8D1BF94F8A003EC431 /* ASEqualityHashHelpers.mm in Sources */,
 				254C6B871BF94F8A003EC431 /* ASTextKitEntityAttribute.m in Sources */,

AsyncDisplayKit/ASCollectionNode.mm

@@ -10,6 +10,7 @@
 #import "ASCollectionInternal.h"
 #import "ASCollectionViewLayoutFacilitatorProtocol.h"
 #import "ASDisplayNode+Subclasses.h"
+#import "ASEnvironmentInternal.h"
 #import "ASRangeControllerUpdateRangeProtocol+Beta.h"
 #include <vector>
 
@@ -244,4 +245,6 @@
   [self.view reloadDataImmediately];
 }
 
+ASDisplayTraitsCollectionTableSetEnvironmentState
+
 @end

AsyncDisplayKit/ASCollectionView.mm

@@ -91,7 +91,7 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
 #pragma mark -
 #pragma mark ASCollectionView.
 
-@interface ASCollectionView () <ASRangeControllerDataSource, ASRangeControllerDelegate, ASDataControllerSource, ASCellNodeLayoutDelegate, ASDelegateProxyInterceptor, ASBatchFetchingScrollView> {
+@interface ASCollectionView () <ASRangeControllerDataSource, ASRangeControllerDelegate, ASDataControllerSource, ASCellNodeLayoutDelegate, ASDelegateProxyInterceptor, ASBatchFetchingScrollView, ASDataControllerEnvironmentDelegate> {
   ASCollectionViewProxy *_proxyDataSource;
   ASCollectionViewProxy *_proxyDelegate;
   
@@ -225,6 +225,7 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
   _dataController = [[ASCollectionDataController alloc] initWithAsyncDataFetching:NO];
   _dataController.delegate = _rangeController;
   _dataController.dataSource = self;
+  _dataController.environmentDelegate = self;
   
   _batchContext = [[ASBatchContext alloc] init];
   
@@ -917,6 +918,14 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
   }
 }
 
+- (id<ASEnvironment>)dataControllerEnvironment
+{
+  if (self.collectionNode) {
+    return self.collectionNode;
+  }
+  return self.strongCollectionNode;
+}
+
 #pragma mark - ASCollectionViewDataControllerSource Supplementary view support
 
 - (ASCellNode *)dataController:(ASCollectionDataController *)dataController supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath

AsyncDisplayKit/ASDisplayNode.mm

@@ -2687,11 +2687,13 @@ static const char *ASDisplayNodeDrawingPriorityKey = "ASDrawingPriority";
 
 - (ASEnvironmentState)environmentState
 {
+  ASDN::MutexLocker l(_propertyLock);
   return _environmentState;
 }
 
 - (void)setEnvironmentState:(ASEnvironmentState)environmentState
 {
+  ASDN::MutexLocker l(_propertyLock);
   _environmentState = environmentState;
 }
 
@@ -2707,7 +2709,12 @@ static const char *ASDisplayNodeDrawingPriorityKey = "ASDrawingPriority";
 
 - (BOOL)supportsUpwardPropagation
 {
-  return ASEnvironmentStatePropagationEnabled();
+  return ASEnvironmentStateUpwardPropagationEnabled();
+}
+
+- (BOOL)supportsDownwardPropagation
+{
+  return ASEnvironmentStateDownwardPropagationEnabled();
 }
 
 ASEnvironmentLayoutOptionsForwarding

AsyncDisplayKit/ASTableNode.mm

@@ -6,6 +6,7 @@
 //  Copyright © 2015 Facebook. All rights reserved.
 //
 
+#import "ASEnvironmentInternal.h"
 #import "ASFlowLayoutController.h"
 #import "ASTableViewInternal.h"
 #import "ASDisplayNode+Subclasses.h"
@@ -158,4 +159,6 @@
   [self.view clearFetchedData];
 }
 
+ASDisplayTraitsCollectionTableSetEnvironmentState
+
 @end

AsyncDisplayKit/ASTableView.mm

@@ -16,6 +16,7 @@
 #import "ASDisplayNodeExtras.h"
 #import "ASDisplayNode+Beta.h"
 #import "ASDisplayNode+FrameworkPrivate.h"
+#import "ASEnvironmentInternal.h"
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
 #import "ASLayoutController.h"
@@ -88,7 +89,7 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
 - (instancetype)_initWithTableView:(ASTableView *)tableView;
 @end
 
-@interface ASTableView () <ASRangeControllerDataSource, ASRangeControllerDelegate, ASDataControllerSource,     _ASTableViewCellDelegate, ASCellNodeLayoutDelegate, ASDelegateProxyInterceptor, ASBatchFetchingScrollView>
+@interface ASTableView () <ASRangeControllerDataSource, ASRangeControllerDelegate, ASDataControllerSource, _ASTableViewCellDelegate, ASCellNodeLayoutDelegate, ASDelegateProxyInterceptor, ASBatchFetchingScrollView, ASDataControllerEnvironmentDelegate>
 {
   ASTableViewProxy *_proxyDataSource;
   ASTableViewProxy *_proxyDelegate;
@@ -175,6 +176,7 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   _dataController = [[dataControllerClass alloc] initWithAsyncDataFetching:NO];
   _dataController.dataSource = self;
   _dataController.delegate = _rangeController;
+  _dataController.environmentDelegate = self;
   
   _layoutController.dataSource = _dataController;
 
@@ -1078,6 +1080,16 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   }
 }
 
+#pragma mark - ASDataControllerEnvironmentDelegate
+
+- (id<ASEnvironment>)dataControllerEnvironment
+{
+  if (self.tableNode) {
+    return self.tableNode;
+  }
+  return self.strongTableNode;
+}
+
 #pragma mark - _ASTableViewCellDelegate
 
 - (void)didLayoutSubviewsOfTableViewCell:(_ASTableViewCell *)tableViewCell

AsyncDisplayKit/ASViewController.h

@@ -11,12 +11,27 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+typedef ASDisplayTraits (^ASDisplayTraitsForTraitCollectionBlock)(UITraitCollection *traitCollection);
+typedef ASDisplayTraits (^ASDisplayTraitsForTraitWindowSizeBlock)(CGSize windowSize);
+
 @interface ASViewController<__covariant DisplayNodeType : ASDisplayNode *> : UIViewController
 
 - (instancetype)initWithNode:(DisplayNodeType)node NS_DESIGNATED_INITIALIZER;
 
 @property (nonatomic, strong, readonly) DisplayNodeType node;
 
+@property (nonatomic, strong) id displayTraitsContext;
+
+/**
+ * Set this block to customize the ASDisplayTraits returned when the VC transitions to the given traitCollection.
+ */
+@property (nonatomic, copy) ASDisplayTraitsForTraitCollectionBlock overrideDisplayTraitsWithTraitCollection;
+
+/**
+ * Set this block to customize the ASDisplayTraits returned when the VC transitions to the given window size.
+ */
+@property (nonatomic, copy) ASDisplayTraitsForTraitWindowSizeBlock overrideDisplayTraitsWithWindowSize;
+
 /**
  * @abstract Passthrough property to the the .interfaceState of the node.
  * @return The current ASInterfaceState of the node, indicating whether it is visible and other situational properties.

AsyncDisplayKit/ASViewController.mm

@@ -11,6 +11,7 @@
 #import "ASDimension.h"
 #import "ASDisplayNode+FrameworkPrivate.h"
 #import "ASDisplayNode+Beta.h"
+#import "ASEnvironmentInternal.h"
 #import "ASRangeControllerUpdateRangeProtocol+Beta.h"
 
 @implementation ASViewController
@@ -46,6 +47,14 @@
   return self;
 }
 
+- (void)dealloc
+{
+  if (_displayTraitsContext != nil) {
+    ASDisplayTraitsClearDisplayContext(self.node);
+    _displayTraitsContext = nil;
+  }
+}
+
 - (void)loadView
 {
   ASDisplayNodeAssertTrue(!_node.layerBacked);
@@ -132,4 +141,66 @@
   return _node.interfaceState;
 }
 
+#pragma mark - ASDisplayTraits
+
+- (ASDisplayTraits)displayTraitsForTraitCollection:(UITraitCollection *)traitCollection
+{
+  if (self.overrideDisplayTraitsWithTraitCollection) {
+    return self.overrideDisplayTraitsWithTraitCollection(traitCollection);
+  }
+  
+  ASDisplayTraits displayTraits = ASDisplayTraitsFromUITraitCollection(traitCollection);
+  displayTraits.displayContext = _displayTraitsContext;
+  return displayTraits;
+}
+
+- (ASDisplayTraits)displayTraitsForWindowSize:(CGSize)windowSize
+{
+  if (self.overrideDisplayTraitsWithWindowSize) {
+    return self.overrideDisplayTraitsWithWindowSize(windowSize);
+  }
+  return self.node.environmentState.displayTraits;
+}
+
+- (void)progagateNewDisplayTraits:(ASDisplayTraits)displayTraits
+{
+  ASEnvironmentState environmentState = self.node.environmentState;
+  ASDisplayTraits oldDisplayTraits = environmentState.displayTraits;
+  
+  if (ASDisplayTraitsIsEqualToASDisplayTraits(displayTraits, oldDisplayTraits) == NO) {
+    environmentState.displayTraits = displayTraits;
+    [self.node setEnvironmentState:environmentState];
+    [self.node setNeedsLayout];
+    
+    NSArray<id<ASEnvironment>> *children = [self.node children];
+    for (id<ASEnvironment> child in children) {
+      ASEnvironmentStatePropagateDown(child, environmentState.displayTraits);
+    }
+  }
+}
+
+- (void)traitCollectionDidChange:(UITraitCollection *)previousTraitCollection
+{
+  [super traitCollectionDidChange:previousTraitCollection];
+  
+  ASDisplayTraits displayTraits = [self displayTraitsForTraitCollection:self.traitCollection];
+  [self progagateNewDisplayTraits:displayTraits];
+}
+
+- (void)willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
+{
+  [super willTransitionToTraitCollection:newCollection withTransitionCoordinator:coordinator];
+  
+  ASDisplayTraits displayTraits = [self displayTraitsForTraitCollection:self.traitCollection];
+  [self progagateNewDisplayTraits:displayTraits];
+}
+
+- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
+{
+  [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
+  
+  ASDisplayTraits displayTraits = [self displayTraitsForWindowSize:size];
+  [self progagateNewDisplayTraits:displayTraits];
+}
+
 @end

AsyncDisplayKit/Details/ASDataController.h

@@ -17,6 +17,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @class ASCellNode;
 @class ASDataController;
+@protocol ASEnvironment;
 
 typedef NSUInteger ASDataControllerAnimationOptions;
 
@@ -64,6 +65,11 @@ FOUNDATION_EXPORT NSString * const ASDataControllerRowNodeKind;
  */
 - (void)dataControllerUnlockDataSource;
 
+
+@end
+
+@protocol ASDataControllerEnvironmentDelegate
+- (id<ASEnvironment>)dataControllerEnvironment;
 @end
 
 /**
@@ -122,6 +128,11 @@ FOUNDATION_EXPORT NSString * const ASDataControllerRowNodeKind;
  */
 @property (nonatomic, weak) id<ASDataControllerDelegate> delegate;
 
+/**
+ *
+ */
+@property (nonatomic, weak) id<ASDataControllerEnvironmentDelegate> environmentDelegate;
+
 /**
  *  Designated initializer.
  *

AsyncDisplayKit/Details/ASDataController.mm

@@ -13,6 +13,7 @@
 #import "ASAssert.h"
 #import "ASCellNode.h"
 #import "ASDisplayNode.h"
+#import "ASEnvironmentInternal.h"
 #import "ASFlowLayoutController.h"
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
@@ -519,8 +520,17 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
     for (NSUInteger i = 0; i < rowNum; i++) {
       NSIndexPath *indexPath = [sectionIndex indexPathByAddingIndex:i];
       ASCellNodeBlock nodeBlock = [_dataSource dataController:self nodeBlockAtIndexPath:indexPath];
+      
+      // When creating a node, make sure to pass along the current display traits so it will be laid out properly
+      ASCellNodeBlock nodeBlockPropagatingDisplayTraits = ^{
+        ASCellNode *cellNode = nodeBlock();
+        id<ASEnvironment> environment = [self.environmentDelegate dataControllerEnvironment];
+        ASEnvironmentStatePropagateDown(cellNode, [environment environmentState].displayTraits);
+        return cellNode;
+      };
+      
       ASSizeRange constrainedSize = [self constrainedSizeForNodeOfKind:ASDataControllerRowNodeKind atIndexPath:indexPath];
-      [contexts addObject:[[ASIndexedNodeContext alloc] initWithNodeBlock:nodeBlock
+      [contexts addObject:[[ASIndexedNodeContext alloc] initWithNodeBlock:nodeBlockPropagatingDisplayTraits
                                                                 indexPath:indexPath
                                                           constrainedSize:constrainedSize]];
     }

AsyncDisplayKit/Details/ASEnvironment.h

@@ -14,6 +14,8 @@
 #import "ASStackLayoutDefines.h"
 #import "ASRelativeSize.h"
 
+@protocol ASEnvironment;
+@class UITraitCollection;
 
 ASDISPLAYNODE_EXTERN_C_BEGIN
 NS_ASSUME_NONNULL_BEGIN
@@ -59,17 +61,50 @@ typedef struct ASEnvironmentHierarchyState {
   unsigned layoutPending:1; // = NO
 } ASEnvironmentHierarchyState;
 
+#pragma mark - ASDisplayTraits
+
+typedef struct ASDisplayTraits {
+  CGFloat displayScale;
+  UIUserInterfaceSizeClass horizontalSizeClass;
+  UIUserInterfaceIdiom userInterfaceIdiom;
+  UIUserInterfaceSizeClass verticalSizeClass;
+  UIForceTouchCapability forceTouchCapability;
+  
+  // WARNING:
+  // This pointer is in a C struct and therefore not managed by ARC. It is
+  // an unsafe unretained pointer, so when you dereference it you better be
+  // sure that it is valid.
+  //
+  // Use displayContext when you wish to pass view context specific data along with the
+  // trait collcetion to subnodes. This should be a piece of data owned by an
+  // ASViewController, which will ensure that the data is still valid when laying out
+  // its subviews. When the VC is dealloc'ed, the displayContext it created will also
+  // be dealloced but any subnodes that are hanging around (why would they be?) will now
+  // have a displayContext that points to a bad pointer.
+  //
+  // An added precaution is to call ASDisplayTraitsClearDisplayContext from your ASVC's desctructor
+  // which will propagate a nil displayContext to its subnodes.
+  //__unsafe_unretained id displayContext;
+  id __unsafe_unretained displayContext;
+} ASDisplayTraits;
+
+extern void ASDisplayTraitsClearDisplayContext(id<ASEnvironment> rootEnvironment);
+
+extern ASDisplayTraits ASDisplayTraitsFromUITraitCollection(UITraitCollection *traitCollection);
+extern BOOL ASDisplayTraitsIsEqualToASDisplayTraits(ASDisplayTraits displayTraits0, ASDisplayTraits displayTraits1);
 
 #pragma mark - ASEnvironmentState
 
 typedef struct ASEnvironmentState {
   struct ASEnvironmentHierarchyState hierarchyState;
   struct ASEnvironmentLayoutOptionsState layoutOptionsState;
+  struct ASDisplayTraits displayTraits;
 } ASEnvironmentState;
 extern ASEnvironmentState ASEnvironmentStateMakeDefault();
 
 ASDISPLAYNODE_EXTERN_C_END
 
+@class ASTraitCollection;
 
 #pragma mark - ASEnvironment
 
@@ -93,6 +128,33 @@ ASDISPLAYNODE_EXTERN_C_END
 /// Classes should implement this method and return YES / NO dependent if upward propagation is enabled or not 
 - (BOOL)supportsUpwardPropagation;
 
+/// Classes should implement this method and return YES / NO dependent if downware propagation is enabled or not
+- (BOOL)supportsDownwardPropagation;
+
 @end
 
+// ASCollection/TableNodes don't actually have ASCellNodes as subnodes. Because of this we can't rely on display trait
+// downward propagation via ASEnvironment. Instead if the new environmentState has displayTraits that are different from
+// the cells', then we propagate downward explicitly and request a relayout.
+//
+// If there is any new downward propagating state, it should be added to this define.
+//
+// This logic is used in both ASCollectionNode and ASTableNode
+#define ASDisplayTraitsCollectionTableSetEnvironmentState \
+- (void)setEnvironmentState:(ASEnvironmentState)environmentState\
+{\
+  ASDisplayTraits oldDisplayTraits = self.environmentState.displayTraits;\
+  [super setEnvironmentState:environmentState];\
+  ASDisplayTraits currentDisplayTraits = environmentState.displayTraits;\
+  if (ASDisplayTraitsIsEqualToASDisplayTraits(currentDisplayTraits, oldDisplayTraits) == NO) {\
+    NSArray<NSArray <ASCellNode *> *> *completedNodes = [self.view.dataController completedNodes];\
+    for (NSArray *sectionArray in completedNodes) {\
+      for (ASCellNode *cellNode in sectionArray) {\
+        ASEnvironmentStatePropagateDown(cellNode, currentDisplayTraits);\
+        [cellNode setNeedsLayout];\
+      }\
+    }\
+  }\
+}\
+
 NS_ASSUME_NONNULL_END

AsyncDisplayKit/Details/ASEnvironment.m

@@ -1,33 +0,0 @@
-/*
- *  Copyright (c) 2014-present, Facebook, Inc.
- *  All rights reserved.
- *
- *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant
- *  of patent rights can be found in the PATENTS file in the same directory.
- *
- */
-
-#import "ASEnvironment.h"
-
-ASEnvironmentLayoutOptionsState _ASEnvironmentLayoutOptionsStateMakeDefault()
-{
-  return (ASEnvironmentLayoutOptionsState) {
-    // Default values can be defined in here
-  };
-}
-
-ASEnvironmentHierarchyState _ASEnvironmentHierarchyStateMakeDefault()
-{
-  return (ASEnvironmentHierarchyState) {
-    // Default values can be defined in here
-  };
-}
-
-ASEnvironmentState ASEnvironmentStateMakeDefault()
-{
-  return (ASEnvironmentState) {
-    .layoutOptionsState = _ASEnvironmentLayoutOptionsStateMakeDefault(),
-    .hierarchyState = _ASEnvironmentHierarchyStateMakeDefault()
-  };
-}

AsyncDisplayKit/Details/ASEnvironment.mm

@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import "ASEnvironment.h"
+#import "ASEnvironmentInternal.h"
+
+ASEnvironmentLayoutOptionsState _ASEnvironmentLayoutOptionsStateMakeDefault()
+{
+  return (ASEnvironmentLayoutOptionsState) {
+    // Default values can be defined in here
+  };
+}
+
+ASEnvironmentHierarchyState _ASEnvironmentHierarchyStateMakeDefault()
+{
+  return (ASEnvironmentHierarchyState) {
+    // Default values can be defined in here
+  };
+}
+
+extern void ASDisplayTraitsClearDisplayContext(id<ASEnvironment> rootEnvironment)
+{
+  ASEnvironmentState envState = [rootEnvironment environmentState];
+  ASDisplayTraits displayTraits = envState.displayTraits;
+  displayTraits.displayContext = nil;
+  envState.displayTraits = displayTraits;
+  [rootEnvironment setEnvironmentState:envState];
+  
+  for (id<ASEnvironment> child in [rootEnvironment children]) {
+    ASEnvironmentStatePropagateDown(child, displayTraits);
+  }
+}
+
+ASDisplayTraits _ASDisplayTraitsMakeDefault()
+{
+  return (ASDisplayTraits) {
+    // Default values can be defined in here
+  };
+}
+
+ASDisplayTraits ASDisplayTraitsFromUITraitCollection(UITraitCollection *traitCollection)
+{  
+  return (ASDisplayTraits) {
+    .displayScale = traitCollection.displayScale,
+    .horizontalSizeClass = traitCollection.horizontalSizeClass,
+    .userInterfaceIdiom = traitCollection.userInterfaceIdiom,
+    .verticalSizeClass = traitCollection.verticalSizeClass,
+    .forceTouchCapability = traitCollection.forceTouchCapability,
+  };
+}
+
+BOOL ASDisplayTraitsIsEqualToASDisplayTraits(ASDisplayTraits displayTraits0, ASDisplayTraits displayTraits1)
+{
+  return
+  displayTraits0.verticalSizeClass == displayTraits1.verticalSizeClass &&
+  displayTraits0.horizontalSizeClass == displayTraits1.horizontalSizeClass &&
+  displayTraits0.displayScale == displayTraits1.displayScale &&
+  displayTraits0.userInterfaceIdiom == displayTraits1.userInterfaceIdiom &&
+  displayTraits0.forceTouchCapability == displayTraits1.forceTouchCapability;
+}
+
+ASEnvironmentState ASEnvironmentStateMakeDefault()
+{
+  return (ASEnvironmentState) {
+    .layoutOptionsState = _ASEnvironmentLayoutOptionsStateMakeDefault(),
+    .hierarchyState = _ASEnvironmentHierarchyStateMakeDefault(),
+    .displayTraits = _ASDisplayTraitsMakeDefault()
+  };
+}
+

AsyncDisplayKit/Layout/ASLayoutSpec.mm

@@ -80,7 +80,7 @@
 
     id<ASLayoutable> finalLayoutable = [child finalLayoutable];
     if (finalLayoutable != child) {
-      if (ASEnvironmentStatePropagationEnabled()) {
+      if (ASEnvironmentStateUpwardPropagationEnabled()) {
         ASEnvironmentStatePropagateUp(finalLayoutable, child.environmentState.layoutOptionsState);
       } else {
         // If state propagation is not enabled the layout options state needs to be copied manually
@@ -168,11 +168,13 @@
 
 - (ASEnvironmentState)environmentState
 {
+  ASDN::MutexLocker l(_propertyLock);
   return _environmentState;
 }
 
 - (void)setEnvironmentState:(ASEnvironmentState)environmentState
 {
+  ASDN::MutexLocker l(_propertyLock);
   _environmentState = environmentState;
 }
 
@@ -181,7 +183,12 @@
 // the specifications that are known to have more than one.
 - (BOOL)supportsUpwardPropagation
 {
-  return ASEnvironmentStatePropagationEnabled();
+  return ASEnvironmentStateUpwardPropagationEnabled();
+}
+
+- (BOOL)supportsDownwardPropagation
+{
+  return ASEnvironmentStateDownwardPropagationEnabled();
 }
 
 - (void)propagateUpLayoutable:(id<ASLayoutable>)layoutable

AsyncDisplayKit/Layout/ASLayoutablePrivate.h

@@ -79,7 +79,7 @@ extern void ASLayoutableClearCurrentContext();
 #define ASEnvironmentLayoutOptionsForwarding \
 - (void)propagateUpLayoutOptionsState\
 {\
-  if (!ASEnvironmentStatePropagationEnabled()) {\
+  if (!ASEnvironmentStateUpwardPropagationEnabled()) {\
     return;\
   }\
   id<ASEnvironment> parent = [self parent];\

AsyncDisplayKit/Private/ASEnvironmentInternal.h

@@ -12,7 +12,8 @@
 
 #pragma once
 
-BOOL ASEnvironmentStatePropagationEnabled();
+BOOL ASEnvironmentStateUpwardPropagationEnabled();
+BOOL ASEnvironmentStateDownwardPropagationEnabled();
 
 
 #pragma mark - Set and get extensible values for layout options
@@ -45,10 +46,12 @@ static const struct ASEnvironmentStateExtensions ASEnvironmentDefaultStateExtens
 static const struct ASEnvironmentLayoutOptionsState ASEnvironmentDefaultLayoutOptionsState = {};
 ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentLayoutOptionsState state, ASEnvironmentStatePropagation propagation);
 
-
 static const struct ASEnvironmentHierarchyState ASEnvironmentDefaultHierarchyState = {};
 ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentHierarchyState state, ASEnvironmentStatePropagation propagation);
 
+static const struct ASDisplayTraits ASEnvironmentDefaultDisplayTraits = {};
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASDisplayTraits state, ASEnvironmentStatePropagation propagation);
+
 
 #pragma mark - Propagation
 

AsyncDisplayKit/Private/ASEnvironmentInternal.mm

@@ -15,11 +15,17 @@
 //#define LOG(...) NSLog(__VA_ARGS__)
 #define LOG(...)
 
-#define AS_SUPPORT_PROPAGATION NO
+#define AS_SUPPORT_UPWARD_PROPAGATION NO
+#define AS_SUPPORT_DOWNWARD_PROPAGATION YES
 
-BOOL ASEnvironmentStatePropagationEnabled()
+BOOL ASEnvironmentStateUpwardPropagationEnabled()
 {
-  return AS_SUPPORT_PROPAGATION;
+  return AS_SUPPORT_UPWARD_PROPAGATION;
+}
+
+BOOL ASEnvironmentStateDownwardPropagationEnabled()
+{
+  return AS_SUPPORT_DOWNWARD_PROPAGATION;
 }
 
 
@@ -106,15 +112,15 @@ UIEdgeInsets _ASEnvironmentLayoutOptionsExtensionGetEdgeInsetsAtIndex(id<ASEnvir
 
 ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentHierarchyState hierarchyState, ASEnvironmentStatePropagation propagation) {
     // Merge object and hierarchy state
-  LOG(@"Merge object and state: %@ - ASEnvironmentHierarchyState", object);
+  LOG(@"Merge object and state: %@ - ASEnvironmentHierarchyState", hierarchyState);
   return environmentState;
 }
 
 ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentLayoutOptionsState layoutOptionsState, ASEnvironmentStatePropagation propagation) {
   // Merge object and layout options state
-  LOG(@"Merge object and state: %@ - ASEnvironmentLayoutOptionsState", object);
+  LOG(@"Merge object and state: %@ - ASEnvironmentLayoutOptionsState", layoutOptionsState);
   
-  if (!ASEnvironmentStatePropagationEnabled()) {
+  if (!ASEnvironmentStateUpwardPropagationEnabled() && propagation == ASEnvironmentStatePropagation::UP) {
     return environmentState;
   }
   
@@ -188,3 +194,23 @@ ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environme
   
   return environmentState;
 }
+
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState childEnvironmentState, ASDisplayTraits parentDisplayTraits, ASEnvironmentStatePropagation propagation) {
+  if (propagation == ASEnvironmentStatePropagation::DOWN && !ASEnvironmentStateDownwardPropagationEnabled()) {
+    return childEnvironmentState;
+  }
+  
+  // Support propagate down
+  if (propagation == ASEnvironmentStatePropagation::DOWN) {
+    ASDisplayTraits childDisplayTraits = childEnvironmentState.displayTraits;
+    childDisplayTraits.horizontalSizeClass = parentDisplayTraits.horizontalSizeClass;
+    childDisplayTraits.verticalSizeClass = parentDisplayTraits.verticalSizeClass;
+    childDisplayTraits.userInterfaceIdiom = parentDisplayTraits.userInterfaceIdiom;
+    childDisplayTraits.forceTouchCapability = parentDisplayTraits.forceTouchCapability;
+    childDisplayTraits.displayScale = parentDisplayTraits.displayScale;
+    childDisplayTraits.displayContext = parentDisplayTraits.displayContext;
+    childEnvironmentState.displayTraits = childDisplayTraits;
+
+  }
+  return childEnvironmentState;
+}

examples/DisplayTraits/Podfile

@@ -0,0 +1,3 @@
+source 'https://github.com/CocoaPods/Specs.git'
+platform :ios, '8.0'
+pod 'AsyncDisplayKit', :path => '../..'

examples/DisplayTraits/Sample.xcodeproj/project.pbxproj

@@ -0,0 +1,379 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
+	};
+	objectVersion = 46;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		05E2128719D4DB510098F589 /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 05E2128619D4DB510098F589 /* main.m */; };
+		05E2128A19D4DB510098F589 /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 05E2128919D4DB510098F589 /* AppDelegate.m */; };
+		05E2128D19D4DB510098F589 /* ViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 05E2128C19D4DB510098F589 /* ViewController.m */; };
+		3EC0CDCBA10D483D9F386E5E /* libPods.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 3D24B17D1E4A4E7A9566C5E9 /* libPods.a */; };
+		9C37D01E1CC94BC9004C8BC1 /* Launch Screen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 9C37D01D1CC94BC9004C8BC1 /* Launch Screen.storyboard */; };
+		9CACC7811CCEAF9E009A1613 /* TableViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 9CACC7801CCEAF9E009A1613 /* TableViewController.m */; };
+		9CACC7841CCEAFAE009A1613 /* CollectionViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 9CACC7831CCEAFAE009A1613 /* CollectionViewController.m */; };
+		9CACC7871CCEBD3B009A1613 /* KittenNode.m in Sources */ = {isa = PBXBuildFile; fileRef = 9CACC7861CCEBD3B009A1613 /* KittenNode.m */; };
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+			isa = PBXGroup;
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+				05E2128519D4DB510098F589 /* Info.plist */,
+				05E2128619D4DB510098F589 /* main.m */,
+				9C37D01D1CC94BC9004C8BC1 /* Launch Screen.storyboard */,
+			);
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+		};
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+				3D24B17D1E4A4E7A9566C5E9 /* libPods.a */,
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+			);
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+			);
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+			attributes = {
+				LastUpgradeCheck = 0600;
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+			showEnvVarsInLog = 0;
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+			buildActionMask = 2147483647;
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+			);
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+			shellPath = /bin/sh;
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods/Pods-resources.sh\"\n";
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+		};
+		FFF65E837E66ADA71296F0FF /* Embed Pods Frameworks */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
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+/* End PBXShellScriptBuildPhase section */
+
+/* Begin PBXSourcesBuildPhase section */
+		05E2127D19D4DB510098F589 /* Sources */ = {
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+
+/* Begin XCBuildConfiguration section */
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+			isa = XCBuildConfiguration;
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+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
+				COPY_PHASE_STRIP = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_DYNAMIC_NO_PIC = NO;
+				GCC_OPTIMIZATION_LEVEL = 0;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"$(inherited)",
+				);
+				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				MTL_ENABLE_DEBUG_INFO = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = iphoneos;
+			};
+			name = Debug;
+		};
+		05E212A319D4DB510098F589 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
+				COPY_PHASE_STRIP = YES;
+				ENABLE_NS_ASSERTIONS = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				MTL_ENABLE_DEBUG_INFO = NO;
+				SDKROOT = iphoneos;
+				VALIDATE_PRODUCT = YES;
+			};
+			name = Release;
+		};
+		05E212A519D4DB510098F589 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = C068F1D3F0CC317E895FCDAB /* Pods.debug.xcconfig */;
+			buildSettings = {
+				INFOPLIST_FILE = Sample/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Debug;
+		};
+		05E212A619D4DB510098F589 /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 088AA6578212BE9BFBB07B70 /* Pods.release.xcconfig */;
+			buildSettings = {
+				INFOPLIST_FILE = Sample/Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Release;
+		};
+/* End XCBuildConfiguration section */
+
+/* Begin XCConfigurationList section */
+		05E2127C19D4DB510098F589 /* Build configuration list for PBXProject "Sample" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				05E212A219D4DB510098F589 /* Debug */,
+				05E212A319D4DB510098F589 /* Release */,
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+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		05E212A419D4DB510098F589 /* Build configuration list for PBXNativeTarget "Sample" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				05E212A519D4DB510098F589 /* Debug */,
+				05E212A619D4DB510098F589 /* Release */,
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+			defaultConfigurationName = Release;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = 05E2127919D4DB510098F589 /* Project object */;
+}

examples/DisplayTraits/Sample.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:Sample.xcodeproj">
+   </FileRef>
+</Workspace>

examples/DisplayTraits/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme

@@ -0,0 +1,88 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0620"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "05E2128019D4DB510098F589"
+               BuildableName = "Sample.app"
+               BlueprintName = "Sample"
+               ReferencedContainer = "container:Sample.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      buildConfiguration = "Debug">
+      <Testables>
+      </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "05E2128019D4DB510098F589"
+            BuildableName = "Sample.app"
+            BlueprintName = "Sample"
+            ReferencedContainer = "container:Sample.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+   </TestAction>
+   <LaunchAction
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      buildConfiguration = "Debug"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "05E2128019D4DB510098F589"
+            BuildableName = "Sample.app"
+            BlueprintName = "Sample"
+            ReferencedContainer = "container:Sample.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      buildConfiguration = "Release"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "05E2128019D4DB510098F589"
+            BuildableName = "Sample.app"
+            BlueprintName = "Sample"
+            ReferencedContainer = "container:Sample.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

examples/DisplayTraits/Sample.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Sample.xcodeproj">
+   </FileRef>
+   <FileRef
+      location = "group:Pods/Pods.xcodeproj">
+   </FileRef>
+</Workspace>

examples/DisplayTraits/Sample/AppDelegate.h

@@ -0,0 +1,20 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <UIKit/UIKit.h>
+
+#define UseAutomaticLayout 1
+
+@interface AppDelegate : UIResponder <UIApplicationDelegate>
+
+@property (strong, nonatomic) UIWindow *window;
+
+@end

examples/DisplayTraits/Sample/AppDelegate.m

@@ -0,0 +1,31 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "AppDelegate.h"
+
+#import "ViewController.h"
+#import "TableViewController.h"
+#import "CollectionViewController.h"
+
+@implementation AppDelegate
+
+- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+{
+  self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
+  self.window.backgroundColor = [UIColor whiteColor];
+  UITabBarController *tabController = [[UITabBarController alloc] init];
+  [tabController setViewControllers:@[[[ViewController alloc] init], [[TableViewController alloc] init], [[CollectionViewController alloc] init]]];
+  self.window.rootViewController = tabController;
+  [self.window makeKeyAndVisible];
+  return YES;
+}
+
+@end

examples/DisplayTraits/Sample/CollectionViewController.h

@@ -0,0 +1,15 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+
+@interface CollectionViewController : ASViewController<ASCollectionNode *>
+@end

examples/DisplayTraits/Sample/CollectionViewController.m

@@ -0,0 +1,72 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "CollectionViewController.h"
+#import "KittenNode.h"
+
+@interface CollectionViewController () <ASCollectionDelegate, ASCollectionDataSource>
+@property (nonatomic, strong) ASCollectionNode *collectionNode;
+@end
+
+@implementation CollectionViewController
+
+- (instancetype)init
+{
+  UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
+  layout.minimumLineSpacing = 10;
+  layout.minimumInteritemSpacing = 10;
+  
+  ASCollectionNode *collectionNode = [[ASCollectionNode alloc] initWithCollectionViewLayout:layout];
+  
+  if (!(self = [super initWithNode:collectionNode]))
+    return nil;
+  
+  self.title = @"Collection Node";
+  _collectionNode = collectionNode;
+  collectionNode.dataSource = self;
+  collectionNode.delegate = self;
+  return self;
+}
+
+- (void)viewDidLoad
+{
+  [super viewDidLoad];
+  self.collectionNode.view.contentInset = UIEdgeInsetsMake(20, 10, CGRectGetHeight(self.tabBarController.tabBar.frame), 10);
+}
+
+#pragma mark - ASCollectionDataSource
+
+- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
+{
+  return 50;
+}
+
+- (ASCellNode *)collectionView:(ASCollectionView *)collectionView nodeForItemAtIndexPath:(NSIndexPath *)indexPath
+{
+  KittenNode *cell = [[KittenNode alloc] init];
+  cell.textNode.maximumNumberOfLines = 3;
+  cell.imageTappedBlock = ^{
+    [KittenNode defaultImageTappedAction:self];
+  };
+  return cell;
+}
+
+- (ASSizeRange)collectionView:(ASCollectionView *)collectionView constrainedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath
+{
+  ASDisplayTraits displayTraits = self.collectionNode.environmentState.displayTraits;
+  
+  if (displayTraits.horizontalSizeClass == UIUserInterfaceSizeClassRegular) {
+    return ASSizeRangeMake(CGSizeMake(200, 120), CGSizeMake(200, 120));
+  }
+  return ASSizeRangeMake(CGSizeMake(132, 180), CGSizeMake(132, 180));
+}
+
+@end

examples/DisplayTraits/Sample/Info.plist

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>com.facebook.AsyncDisplayKit.$(PRODUCT_NAME:rfc1034identifier)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>Launch Screen</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>armv7</string>
+	</array>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+	</array>
+</dict>
+</plist>

examples/DisplayTraits/Sample/KittenNode.h

@@ -0,0 +1,23 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+
+@interface KittenNode : ASCellNode
+@property (nonatomic, strong, readonly) ASNetworkImageNode *imageNode;
+@property (nonatomic, strong, readonly) ASTextNode *textNode;
+
+@property (nonatomic, copy) dispatch_block_t imageTappedBlock;
+
+// The default action when an image node is tapped. This action will create an
+// OverrideVC and override its display traits to always be compact.
++ (void)defaultImageTappedAction:(ASViewController *)sourceViewController;
+@end

examples/DisplayTraits/Sample/KittenNode.m

@@ -0,0 +1,170 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "KittenNode.h"
+#import "OverrideViewController.h"
+
+static const CGFloat kOuterPadding = 16.0f;
+static const CGFloat kInnerPadding = 10.0f;
+
+@interface KittenNode ()
+{
+  CGSize _kittenSize;
+}
+
+@end
+
+
+@implementation KittenNode
+
+// lorem ipsum text courtesy https://kittyipsum.com/ <3
++ (NSArray *)placeholders
+{
+  static NSArray *placeholders = nil;
+  
+  static dispatch_once_t once;
+  dispatch_once(&once, ^{
+    placeholders = @[
+                     @"Kitty ipsum dolor sit amet, purr sleep on your face lay down in your way biting, sniff tincidunt a etiam fluffy fur judging you stuck in a tree kittens.",
+                     @"Lick tincidunt a biting eat the grass, egestas enim ut lick leap puking climb the curtains lick.",
+                     @"Lick quis nunc toss the mousie vel, tortor pellentesque sunbathe orci turpis non tail flick suscipit sleep in the sink.",
+                     @"Orci turpis litter box et stuck in a tree, egestas ac tempus et aliquam elit.",
+                     @"Hairball iaculis dolor dolor neque, nibh adipiscing vehicula egestas dolor aliquam.",
+                     @"Sunbathe fluffy fur tortor faucibus pharetra jump, enim jump on the table I don't like that food catnip toss the mousie scratched.",
+                     @"Quis nunc nam sleep in the sink quis nunc purr faucibus, chase the red dot consectetur bat sagittis.",
+                     @"Lick tail flick jump on the table stretching purr amet, rhoncus scratched jump on the table run.",
+                     @"Suspendisse aliquam vulputate feed me sleep on your keyboard, rip the couch faucibus sleep on your keyboard tristique give me fish dolor.",
+                     @"Rip the couch hiss attack your ankles biting pellentesque puking, enim suspendisse enim mauris a.",
+                     @"Sollicitudin iaculis vestibulum toss the mousie biting attack your ankles, puking nunc jump adipiscing in viverra.",
+                     @"Nam zzz amet neque, bat tincidunt a iaculis sniff hiss bibendum leap nibh.",
+                     @"Chase the red dot enim puking chuf, tristique et egestas sniff sollicitudin pharetra enim ut mauris a.",
+                     @"Sagittis scratched et lick, hairball leap attack adipiscing catnip tail flick iaculis lick.",
+                     @"Neque neque sleep in the sink neque sleep on your face, climb the curtains chuf tail flick sniff tortor non.",
+                     @"Ac etiam kittens claw toss the mousie jump, pellentesque rhoncus litter box give me fish adipiscing mauris a.",
+                     @"Pharetra egestas sunbathe faucibus ac fluffy fur, hiss feed me give me fish accumsan.",
+                     @"Tortor leap tristique accumsan rutrum sleep in the sink, amet sollicitudin adipiscing dolor chase the red dot.",
+                     @"Knock over the lamp pharetra vehicula sleep on your face rhoncus, jump elit cras nec quis quis nunc nam.",
+                     @"Sollicitudin feed me et ac in viverra catnip, nunc eat I don't like that food iaculis give me fish.",
+                     ];
+  });
+  
+  return placeholders;
+}
+
+- (instancetype)init
+{
+  if (!(self = [super init]))
+    return nil;
+  
+  _kittenSize = CGSizeMake(100,100);
+  
+  // kitten image, with a solid background colour serving as placeholder
+  _imageNode = [[ASNetworkImageNode alloc] init];
+  _imageNode.backgroundColor = ASDisplayNodeDefaultPlaceholderColor();
+  _imageNode.preferredFrameSize = _kittenSize;
+  [_imageNode addTarget:self action:@selector(imageTapped:) forControlEvents:ASControlNodeEventTouchUpInside];
+  
+  CGFloat scale = [UIScreen mainScreen].scale;
+  _imageNode.URL = [NSURL URLWithString:[NSString stringWithFormat:@"https://placekitten.com/%zd/%zd?image=%zd",
+                                         (NSInteger)roundl(_kittenSize.width * scale),
+                                         (NSInteger)roundl(_kittenSize.height * scale),
+                                         (NSInteger)arc4random_uniform(20)]];
+  [self addSubnode:_imageNode];
+  
+  // lorem ipsum text, plus some nice styling
+  _textNode = [[ASTextNode alloc] init];
+  _textNode.attributedString = [[NSAttributedString alloc] initWithString:[self kittyIpsum]
+                                                               attributes:[self textStyle]];
+  _textNode.flexShrink = YES;
+  _textNode.flexGrow = YES;
+  [self addSubnode:_textNode];
+  
+  return self;
+}
+
+- (void)imageTapped:(id)sender
+{
+  if (self.imageTappedBlock) {
+    self.imageTappedBlock();
+  }
+}
+
+- (NSString *)kittyIpsum
+{
+  NSArray *placeholders = [KittenNode placeholders];
+  u_int32_t ipsumCount = (u_int32_t)[placeholders count];
+  u_int32_t location = arc4random_uniform(ipsumCount);
+  u_int32_t length = arc4random_uniform(ipsumCount - location);
+  
+  NSMutableString *string = [placeholders[location] mutableCopy];
+  for (u_int32_t i = location + 1; i < location + length; i++) {
+    [string appendString:(i % 2 == 0) ? @"\n" : @"  "];
+    [string appendString:placeholders[i]];
+  }
+  
+  return string;
+}
+
+- (NSDictionary *)textStyle
+{
+  UIFont *font = [UIFont fontWithName:@"HelveticaNeue" size:12.0f];
+  
+  NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
+  style.paragraphSpacing = 0.5 * font.lineHeight;
+  style.hyphenationFactor = 1.0;
+  
+  return @{ NSFontAttributeName: font,
+            NSParagraphStyleAttributeName: style,
+            ASTextNodeWordKerningAttributeName : @.5};
+}
+
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
+  
+  ASDisplayTraits displayTraits = self.environmentState.displayTraits;
+  
+  ASStackLayoutSpec *stackSpec = [[ASStackLayoutSpec alloc] init];
+  stackSpec.spacing = kInnerPadding;
+  stackSpec.children = @[_imageNode, _textNode];
+  
+  if (displayTraits.horizontalSizeClass == UIUserInterfaceSizeClassRegular) {
+    _imageNode.alignSelf = ASStackLayoutAlignSelfStart;
+    stackSpec.direction = ASStackLayoutDirectionHorizontal;
+  } else {
+    _imageNode.alignSelf = ASStackLayoutAlignSelfCenter;
+    stackSpec.direction = ASStackLayoutDirectionVertical;
+  }
+  
+  return [ASInsetLayoutSpec insetLayoutSpecWithInsets:UIEdgeInsetsMake(kOuterPadding, kOuterPadding, kOuterPadding, kOuterPadding) child:stackSpec];
+}
+
+
++ (void)defaultImageTappedAction:(ASViewController *)sourceViewController
+{
+  OverrideViewController *overrideVC = [[OverrideViewController alloc] init];
+  
+  overrideVC.overrideDisplayTraitsWithTraitCollection = ^(UITraitCollection *traitCollection) {
+    return (ASDisplayTraits) {
+      .displayScale = traitCollection.displayScale,
+      .horizontalSizeClass = UIUserInterfaceSizeClassCompact,
+      .userInterfaceIdiom = traitCollection.userInterfaceIdiom,
+      .verticalSizeClass = UIUserInterfaceSizeClassCompact,
+      .forceTouchCapability = traitCollection.forceTouchCapability,
+    };
+  };
+  
+  [sourceViewController presentViewController:overrideVC animated:YES completion:nil];
+  overrideVC.closeBlock = ^{
+    [sourceViewController dismissViewControllerAnimated:YES completion:nil];
+  };
+}
+
+@end

examples/DisplayTraits/Sample/Launch Screen.storyboard

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="10116" systemVersion="15E65" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="10085"/>
+        <capability name="Constraints with non-1.0 multipliers" minToolsVersion="5.1"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Llm-lL-Icb"/>
+                        <viewControllerLayoutGuide type="bottom" id="xb3-aO-Qok"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="  Copyright © 2016 Facebook. All rights reserved." textAlignment="center" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" minimumFontSize="9" translatesAutoresizingMaskIntoConstraints="NO" id="obG-Y5-kRd">
+                                <rect key="frame" x="20" y="559" width="560" height="21"/>
+                                <fontDescription key="fontDescription" type="system" pointSize="17"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                            <label opaque="NO" clipsSubviews="YES" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Display Traits" textAlignment="center" lineBreakMode="middleTruncation" baselineAdjustment="alignBaselines" minimumFontSize="18" translatesAutoresizingMaskIntoConstraints="NO" id="GJd-Yh-RWb">
+                                <rect key="frame" x="20" y="180" width="560" height="43"/>
+                                <fontDescription key="fontDescription" type="boldSystem" pointSize="36"/>
+                                <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>
+                                <nil key="highlightedColor"/>
+                            </label>
+                        </subviews>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
+                        <constraints>
+                            <constraint firstAttribute="centerX" secondItem="obG-Y5-kRd" secondAttribute="centerX" id="5cz-MP-9tL"/>
+                            <constraint firstAttribute="centerX" secondItem="GJd-Yh-RWb" secondAttribute="centerX" id="Q3B-4B-g5h"/>
+                            <constraint firstItem="obG-Y5-kRd" firstAttribute="leading" secondItem="Ze5-6b-2t3" secondAttribute="leading" constant="20" symbolic="YES" id="SfN-ll-jLj"/>
+                            <constraint firstAttribute="bottom" secondItem="obG-Y5-kRd" secondAttribute="bottom" constant="20" id="Y44-ml-fuU"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="bottom" multiplier="1/3" constant="1" id="moa-c2-u7t"/>
+                            <constraint firstItem="GJd-Yh-RWb" firstAttribute="leading" secondItem="Ze5-6b-2t3" secondAttribute="leading" constant="20" symbolic="YES" id="x7j-FC-K8j"/>
+                        </constraints>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="625" y="488"/>
+        </scene>
+    </scenes>
+</document>

examples/DisplayTraits/Sample/OverrideViewController.h

@@ -0,0 +1,29 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+
+/*
+ * A simple node that displays the attribution for the kitties in the app. Note that
+ * for a regular horizontal size class it does something stupid and sets the font size to 100.
+ * It's VC, OverrideViewController, will have its display traits overridden such that
+ * it will always have a compact horizontal size class.
+ */
+@interface OverrideNode : ASDisplayNode
+@end
+
+/*
+ * This is a fairly stupid VC that's main purpose is to show how to override ASDisplayTraits.
+ * Take a look at `defaultImageTappedAction` in KittenNode to see how this is accomplished.
+ */
+@interface OverrideViewController : ASViewController<OverrideNode *>
+@property (nonatomic, copy) dispatch_block_t closeBlock;
+@end

examples/DisplayTraits/Sample/OverrideViewController.m

@@ -0,0 +1,95 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "OverrideViewController.h"
+static NSString *kLinkAttributeName = @"PlaceKittenNodeLinkAttributeName";
+
+@interface OverrideNode()
+@property (nonatomic, strong) ASTextNode *textNode;
+@property (nonatomic, strong) ASButtonNode *buttonNode;
+@end
+
+@implementation OverrideNode
+
+- (instancetype)init
+{
+  if (!(self = [super init]))
+    return nil;
+  
+  _textNode = [[ASTextNode alloc] init];
+  _textNode.flexGrow = YES;
+  _textNode.flexShrink = YES;
+  _textNode.maximumNumberOfLines = 3;
+  [self addSubnode:_textNode];
+  
+  _buttonNode = [[ASButtonNode alloc] init];
+  [_buttonNode setAttributedTitle:[[NSAttributedString alloc] initWithString:@"Close"] forState:ASControlStateNormal];
+  [self addSubnode:_buttonNode];
+  
+  self.backgroundColor = [UIColor lightGrayColor];
+  
+  return self;
+}
+
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
+  CGFloat pointSize = 16.f;
+  ASDisplayTraits displayTraits = self.environmentState.displayTraits;
+  if (displayTraits.horizontalSizeClass == UIUserInterfaceSizeClassRegular) {
+    // This should never happen because we override the VC's display traits to always be compact.
+    pointSize = 100;
+  }
+  
+  NSString *blurb = @"kittens courtesy placekitten.com";
+  NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:blurb];
+  [string addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"HelveticaNeue" size:pointSize] range:NSMakeRange(0, blurb.length)];
+  [string addAttributes:@{
+                          kLinkAttributeName: [NSURL URLWithString:@"http://placekitten.com/"],
+                          NSForegroundColorAttributeName: [UIColor grayColor],
+                          NSUnderlineStyleAttributeName: @(NSUnderlineStyleSingle | NSUnderlinePatternDot),
+                          }
+                  range:[blurb rangeOfString:@"placekitten.com"]];
+  
+  _textNode.attributedString = string;
+  
+  ASStackLayoutSpec *stackSpec = [ASStackLayoutSpec verticalStackLayoutSpec];
+  stackSpec.children = @[_textNode, _buttonNode];
+  stackSpec.spacing = 10;
+  return [ASInsetLayoutSpec insetLayoutSpecWithInsets:UIEdgeInsetsMake(40, 20, 20, 20) child:stackSpec];
+}
+
+@end
+
+@interface OverrideViewController ()
+
+@end
+
+@implementation OverrideViewController
+
+- (instancetype)init
+{
+  OverrideNode *overrideNode = [[OverrideNode alloc] init];
+  
+  if (!(self = [super initWithNode:overrideNode]))
+    return nil;
+  
+  [overrideNode.buttonNode addTarget:self action:@selector(closeTapped:) forControlEvents:ASControlNodeEventTouchUpInside];
+  return self;
+}
+
+- (void)closeTapped:(id)sender
+{
+  if (self.closeBlock) {
+    self.closeBlock();
+  }
+}
+
+@end

examples/DisplayTraits/Sample/TableViewController.h

@@ -0,0 +1,16 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+
+@interface TableViewController : ASViewController<ASTableNode *>
+
+@end

examples/DisplayTraits/Sample/TableViewController.m

@@ -0,0 +1,62 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "TableViewController.h"
+#import "KittenNode.h"
+
+@interface TableViewController () <ASTableViewDataSource, ASTableViewDelegate>
+@property (nonatomic, strong) ASTableNode *tableNode;
+@end
+
+@implementation TableViewController
+
+- (instancetype)init
+{
+  ASTableNode *tableNode = [[ASTableNode alloc] init];
+  if (!(self = [super initWithNode:tableNode]))
+    return nil;
+  
+  _tableNode = tableNode;
+  tableNode.delegate = self;
+  tableNode.dataSource = self;
+  self.title = @"Table Node";
+  return self;
+}
+
+- (void)viewDidLoad
+{
+  [super viewDidLoad];
+  self.tableNode.view.contentInset = UIEdgeInsetsMake(CGRectGetHeight([[UIApplication sharedApplication] statusBarFrame]), 0, CGRectGetHeight(self.tabBarController.tabBar.frame), 0);
+}
+
+#pragma mark -
+#pragma mark ASTableView.
+
+- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
+{
+  [tableView deselectRowAtIndexPath:indexPath animated:YES];
+}
+
+- (ASCellNode *)tableView:(ASTableView *)tableView nodeForRowAtIndexPath:(NSIndexPath *)indexPath
+{
+  KittenNode *cell = [[KittenNode alloc] init];
+  cell.imageTappedBlock = ^{
+    [KittenNode defaultImageTappedAction:self];
+  };
+  return cell;
+}
+
+- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
+{
+  return 15;
+}
+
+@end

examples/DisplayTraits/Sample/ViewController.h

@@ -0,0 +1,16 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+
+@interface ViewController : ASViewController<ASDisplayNode *>
+
+@end

examples/DisplayTraits/Sample/ViewController.m

@@ -0,0 +1,45 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import "ViewController.h"
+#import "KittenNode.h"
+#import "OverrideViewController.h"
+
+#import <AsyncDisplayKit/AsyncDisplayKit.h>
+#import <AsyncDisplayKit/ASAssert.h>
+
+@interface ViewController ()
+@end
+
+@implementation ViewController
+
+#pragma mark -
+#pragma mark UIViewController.
+
+- (instancetype)init
+{
+  KittenNode *displayNode = [[KittenNode alloc] init];
+  if (!(self = [super initWithNode:displayNode]))
+    return nil;
+
+  self.title = @"Display Node";
+  displayNode.imageTappedBlock = ^{
+    [KittenNode defaultImageTappedAction:self];
+  };
+  return self;
+}
+
+- (void)viewWillLayoutSubviews
+{
+  [super viewWillLayoutSubviews];
+}
+
+@end

examples/DisplayTraits/Sample/main.m

@@ -0,0 +1,20 @@
+/* This file provided by Facebook is for non-commercial testing and evaluation
+ * purposes only.  Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#import <UIKit/UIKit.h>
+
+#import "AppDelegate.h"
+
+int main(int argc, char * argv[]) {
+  @autoreleasepool {
+      return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
+  }
+}